hwmon: (ltc2992) Add support

LTC2992 is a rail-to-rail system monitor that
measures current, voltage, and power of two supplies.

Two ADCs simultaneously measure each supply’s current.
A third ADC monitors the input voltages and four
auxiliary external voltages.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -101,6 +101,7 @@ Hardware Monitoring Kernel Drivers
    lm95234
    lm95245
    lochnagar
+   ltc2992
    ltc2945
    ltc2947
    ltc2978

Documentation/hwmon/ltc2992.rst

@@ -0,0 +1,56 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver ltc2992
+=====================
+
+Supported chips:
+  * Linear Technology LTC2992
+    Prefix: 'ltc2992'
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2992.pdf
+
+Author: Alexandru Tachici <alexandru.tachici@analog.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Linear Technology LTC2992 power monitor.
+
+LTC2992 is a rail-to-rail system monitor that measures current,
+voltage, and power of two supplies.
+
+Two ADCs simultaneously measure each supply’s current. A third ADC monitors
+the input voltages and four auxiliary external voltages.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write,
+all other attributes are read-only.
+
+in_reset_history	Reset all highest/lowest values.
+
+inX_input		Measured voltage.
+inX_lowest		Minimum measured voltage.
+inX_highest		Maximum measured voltage.
+inX_min			Minimum voltage allowed.
+inX_max			Maximum voltage allowed.
+inX_min_alarm		An undervoltage occurred. Cleared on read.
+inX_max_alarm		An overvoltage occurred. Cleared on read.
+
+currX_input		Measured current.
+currX_lowest		Minimum measured current.
+currX_highest		Maximum measured current.
+currX_min		Minimum current allowed.
+currX_max		Maximum current allowed.
+currX_min_alarm		An undercurrent occurred. Cleared on read.
+currX_max_alarm		An overcurrent occurred. Cleared on read.
+
+powerX_input		Measured power.
+powerX_input_lowest	Minimum measured voltage.
+powerX_input_highest	Maximum measured voltage.
+powerX_min		Minimum power.
+powerX_max		Maximum power.
+powerX_min_alarm	An underpower occurred. Cleared on read.
+powerX_max_alarm	An overpower occurred. Cleared on read.

drivers/hwmon/Kconfig

@@ -871,6 +871,17 @@ config SENSORS_LTC2990
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc2990.
 
+config SENSORS_LTC2992
+	tristate "Linear Technology LTC2992"
+	depends on I2C
+	help
+	  If you say yes here you get support for Linear Technology LTC2992
+	  I2C System Monitor. The LTC2992 measures current, voltage, and
+	  power of two supplies.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ltc2992.
+
 config SENSORS_LTC4151
 	tristate "Linear Technology LTC4151"
 	depends on I2C

drivers/hwmon/Makefile

@@ -119,6 +119,7 @@ obj-$(CONFIG_SENSORS_LTC2947)	+= ltc2947-core.o
 obj-$(CONFIG_SENSORS_LTC2947_I2C) += ltc2947-i2c.o
 obj-$(CONFIG_SENSORS_LTC2947_SPI) += ltc2947-spi.o
 obj-$(CONFIG_SENSORS_LTC2990)	+= ltc2990.o
+obj-$(CONFIG_SENSORS_LTC2992)	+= ltc2992.o
 obj-$(CONFIG_SENSORS_LTC4151)	+= ltc4151.o
 obj-$(CONFIG_SENSORS_LTC4215)	+= ltc4215.o
 obj-$(CONFIG_SENSORS_LTC4222)	+= ltc4222.o